Page 31 - CHƯƠNG II: GIẢI TÍCH 12-12a2

Trường THPT Châu Phú Chương II: Mũ – Lôgarit INOXHTT
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x
x +
Câu 244: Cho biểu thức B = 3log x − 6log (3 ) log . Biểu thức B được rút gọn thành:
3 9 1 9
3
. AB = log (3 ) x . B B = − log ( ) x . C B = − log (3 ) x . D B = log (3 ) x
3 3 3 3

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Câu 245: log 4 8 bằng:
4
1
3
5
A. B. C. D. 2
2 8 4

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=
+
Câu 247: Nếu log x 5log a 4log b (a, b > 0) thì x bằng:
2 2 2
4 5
5 4
A. a b B. a b C. 5a + 4b D. 4a + 5b
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−
2  1  2 1
Câu 249: Rút gọn biểu thức a   (a > 0), ta được:
 a 
A. a B. 2a C. 3a D. 4a

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